Magneto structure and method of making the same



p 1951 D. A. ARMSTRONG ET AL 2,568,479

MAGNETOSTRUCTURE AND METHOD OF MAKING THE SAME Filed Aug. 9, 1948 2Sheets-Sheet 1 Sept. 18, 1951 D. A. ARMSTRONG ET AL 2,563,479

MAGNETOSTRUCTURE AND METHOD OF MAKING THE SAME Filed Aug. 9, 1948 2Sheets-Sheet 2 Patented Sept. 18, 1951 UNITED STATES PATENT OFFICE.

MAGNETO STRUCTURE AND METHODv OF MAKING THE SAME Application August 9,1948, Serial No. 43,318

6 Claims.

This invention relates to a magneto structure and method of making. thesame, and while the invention is applicable to many forms of mag netm,it has beenparticularly designed for use on a magneto used with anoutboard motor. In the type of magneto usually used with an outboardmotor there is a rotating member which carries one or more magnets. Inthe operation of the magneto this rotating member carries the magnetpast the core of. acoil. It has heretofore been somewhat of a problem tosecure the magnet in the rotating member and to have it carried insuitable magnetic material.

It is an object of this invention to provide a simple and efficientmethod for securing the magnet in its supporting member and forconstructing said member to provide the necessary magnetic paths.

It isa'further object ofthe invention to provide a'simple and eflicientmethod of forming a magnet which consists in spraying-finely dividedmagnetic material against the polar faces of said. magnet, whichmaterial adheres very closely and firmly to said magnet and can. befinished as desired.

It is also an object of the invention to provide a simple and efiicientmethod otsecuring two or more magnets in spaced relation in a.supporting member having magnetically conducting portions which consistsin providing;

magnets, to'the polar faces of which. a highly magnetic material. hasbeen added and casting the metal of said supporting member around saidmagnets, whereby a magnetic path. is formed between said, magnets bysaid'magnetbcally conducting portions of said supporting member.

Itis'alsoan object of this invention toprovide a simple and efficientmethod of forming a. magneto structure which consists in providing a;fixture, placing: magnets in said fixture in spacedirelation, sprayinghighly magnetic material against the polar faces of said'magnets andbetween the adjacent ends thereof and then imbedding said magnets andmagnetic material which form a unit in a non-magnetic cast- It is stilla further object of this invention to provide a magneto structurecomprising a supporting member having one or more magnets casttherein,said magnets having the polar faces thereof formed of highly'magneticmaterial which adheres very closely and firmly to said magnets andwhich: can be finished as desired.

It is still another object of the invention. to

provide a method, of forming a magnet which consists in spraying: ahighly magnetic material against the polar face of said magnet in finelydivided condition whereby said material adheres very closely and firmlyto said face.

These and other objects and advantagesof the invention will be fully setforth in the. following description made inconnection with theaccompanying drawings in which. like reference characters refer tosimilar parts throughout the several views and in which:

Fig. 1 is a plan view of a rotatable support.- ing member adapted tocarry one or more magi nets, some parts being broken away and. othersshown in horizontal section;

Fig. 2 is a vertical section taken on 1ine:2--2 of Fig. 1;

Fig. 3 is a plan view of: a different type of rotatable supportingmember adapted to carryone or 'more magnets, some parts being brokenaway and others shown in horizontal section;

Fig. 4 is a view partly in side elevation'and partly in radial verticalsection of a'member shown. in Fig. .3 and showing additional parts;

Fig; 5 is a. plan view of a rotor adapted tov carry a magnet;

Fig. 6 is a vertical section taken substantially on line 6-6 of Fig.5,as indicated by the arrows;

Fig. 7 is a top plan view of a magnet used; and

Fig. 8 is a view in side elevation of said magnet.

Reierring to the drawings, particularly Figs. 1 and 2, a member i0 isshown, the same being illustrated as substantially cylindrical in form,the same having an outer wall 10a and atop wall lfib; said walls mergingat the upper corner of the device: in curved form. Member Ill has aninner portion lDc which fits within wall ma and which is also ofcylindrical form. In practice, portion 190 is pressed Within wall|'0a'.. Portion I 9c has an inner cylindrical surface lilld and saidportion is of less height than member it. While it could be variouslyformed, as shown in Fig. 2, portion 100 is spaced a slight distance fromthe bottom of outer wall 16a and the top of portion lilo is spaced somedistance from. top wall lllb. Member ID will be suiiably mounted forrotation on a member having a hub secured to the motor shaft. Referenceis made to the previously filed application of Walter J Raleigh, S. N.689,876, filed August 12, 1946, on Magneto, now Patent No. 2,537,856,issued January 9, 1951. Portion lOc is provided at oppositesides means,each as by rivets, etc.

with a plurality of openings We to lessen the weight of the device. Inaccordance with the present invention, magnets II are prepared and castin spaced relation in portion IIlc. These magnets have an iron alloymaterial of highly magnetic permeability secured to their pole faces.

This material is secured to said faces by being sprayed thereagainst infinely divided condition and said material adheres very closely andfirmly to said faces. Magnets II are shown as having grooves I la formedtherein in their top and bottom sides, which grooves are occupied by thecast metal of member Iflc. This grooved structure assists in holdingsaid magnets in place in member I00. Said magnetic material isdesignated in Figs. 1 and 2 as IIb. Said iron alloy or magnetic materialthen extends at the inner and outer sides of said magnets II or alongthe pole faces thereof. In the form shown in Figs. 1 and 2, the outerannular portion IIla.of member III will be made of magnetic material.The surfaces of the'magnetic material at the inner sides of magnet I Iwill then be finished in a true cylindrical surface IIc concentric withmember I and substantially flush with surface IOd. The magnetic materialI lb at the outer faces engages the inner surface of portion I [la and avery fine magnetic path is provided from magnets II to said outerportion Illa. A very fine magnetic path is also provided from magnets IIto the surface I0 Said outer Wall or portion IIJa forms a magnetic pathbetween magnets II. The material sprayed onto the polar faces of magnetsII forms a superior magnetic path over structures having pole facessecured b mechanical The operation of spraying the magnetic material oriron alloy is usually done with a torch or gun especially constructedfor that purpose. The metal usually is in the form of a wire or rod andis fed in at one end of the torch or gun and this metal is fused andforcibly projected in finely divided condition at the other end of thetorch or gun. As stated, the metal adheres very closely and firmly tothe polar faces of the magnet and becomes in effect an integral partthereof. In operation of the structure shown in Figs. 1 and 2, thesurface He will be rotated in Very close proximity to the core of acoil, such as the core I 8a of coil I8 illustrated in Fig. 4.

Referring to Figs. 3 and 4, a member 15 is shown of annular form havinga top portion Ie, downwardly curved sides and a lower annular portionI5b. Member I5 is shown as having a hub I5e secured therein which willbe attached to the motor shaft and a member I! is shown which will besupported on the motor frame and which forms a support for the core I8aof coil I8. Portion I5a has an inner cylindrical surface I5e. Member I5will be made of non-magnetic material, such as aluminum, bronze, zinc orsuitable alloys thereof.

In accordance with the present invention a pair of magnets I6 areprovided. These magnets will be supported in a suitable fixture (notshown) and a layer of iron alloy as mentioned above will be sprayed ontothe polar faces thereof and will thus be firmly secured to said faces.On the outer side this layer of highly magnetic -material Ifia willextend between said magnets, as shown in Fig. 3. The magnets and saidmaterial after being so sprayed will form a unit and will now be removedfrom said fixture and be suitably supported to be cast into member I5.Portion Ifia will form a fine magnet path between magnets 4 I6. Thesprayed magnetic material or iron alloy at the inner side of magnet I6is designated Iliaa. This inner material Ifiaa. will be finished in atrue cylindrical surface I5d concentric with member I5 which will besubstantially flush with surface I50.

The layer of magnetic material IBa shown in Figs. 3 and 4 is necessaryto form a magnetic path between magnets I 6, since member I5 as abovestated is of non-magnetic material. In operation the magnets I6 arecarried past the core I8a and surface I5d of material IEaa passes invery close proximity to said core. A very fine magnetic path is thusprovided by the material I6a and Ifiaa.

Referring to Figs. 5 to 8, a rotatable member is shown comprising ashell 2I having an end portion 2Ia which carries a hub 2Ib. Hub 2Ib isprovided with a bushing 22 which is provided with a taper bore and akeyway for attachment to the rotor shaft. A double magnet 24 isprovided, the same being shaped as shown in Figs. 7 and 8. Said magnet24 is of general arcuate or crescent shape and has a groove 24a,rectangular in cross section extending transversely of its concave side.Said magnet also has a fiatsubstantially rectangular portion 2419 at itsupper side. Magnet 24 will have a highly magnetic ma terial, such as aspecial iron alloy, sprayed against the concave polar faces thereof, asshown in Figs. 5, 6 and 8. Magnet 24 will .be suitably lo: cated inposition by pins extending through openings 2Ia shown in member 2|.Right angular shaped holes 2Ie are provided which also function toreceive clamping members to hold said magnet 24 in position. Magnet 24is then cast into member 2I. It could be held in a receiving member 2Iand metal cast about it after member 2| has been formed. After magnet 24is cast in position the material 25 will be finished on a truecylindrical surface 240 concentric with member 2 I, Member 2I is shownas having there in a counterweight 26 adapted to balance the weight ofmagnet 24. Member 2I will be of magnetic material and there is thus agood magnetic path for the portions of magnet 24 at the outer sidesthereof.

In operation member 2I will be rotated as usual and surface 240 willmove in close prox-- imity to the core of a coil, such as illustrated inFig. 4. A very fine magnetic path is thus provided between the magnetsand said core by the material 25 forming the polar face portions of saidmagnets. The magnetic path or path of the magnetic flux includes thesmall air gap between the polar face of the magnet I6 and the core I8aof the magneto. A highly effec-' tive and efficient passage of the fluxis thus attained.

From the above description it will be seen that we have provided asimple and yet highly efficient magneto structure and method of makingthe same. The operation of spraying the iron alloy onto the magnets iseasily and quickly performed and a highly magnetic pole face is thusprovided and secured to the magnet in a greatly improved manner. Thisface can be easily finished alon the desired surface; Our presentstructure is much less expensive than the ones heretofore used andresults in'greater magnetic efficiency. The structure and method havebeen actually demonstrated in actual prac-' tice and found to be verysuccessful and efficient and will soon be in commercial produc 76 tion.

It will of course be understood that various changes may be made in theform, details, arrangement and proportions of the structure and in thesteps and sequence of steps of the method without departing from thescope of applicants 1 invention, which, generally stated, consists in amethod and structure capable of carrying out the objects above setforth, such as disclosed and defined in the appended claims.

What is claimed is:

l. The method of making a magneto structure comprising a rotor whichconsists in providing a pair of magnets having polar faces at one sidethereof constructed to be disposed at one side of an air gap, sprayingfinely divided fused highly magnetic material onto the polar face ofsaid magnets to cause said material to adhere Very firmly to said faces,holding said magnets in spaced relation and casting a rotor of magneticmaterial about said magnets with the sprayed material on the outer polarfaces of said magnets very closely engaging a magnetic portion of saidrotor whereby said rotor forms a magnetic path between said magnets andsaid sprayed material will be at the side of an air gap when said magnetis in operation.

2. The method set forth in claim 1, with the additional step offinishing the magnetic materials sprayed onto the inner polar surfacesof said magnets in a true cylindrical surface concentric with saidrotor.

3. The method of forming a magneto having a rotor which consists inproviding a pair of magnets having polar faces at opposite sides thereofrespectively, holding said magnets inlongitudinally spaced relation on asuitable fixture, spraying a layer of highly heated and fused highlymagnetic material in finely divided condition onto said polar facesthereof to cause said material to adhere to said faces, forming thelayer at the outer polar face to extend between said magnets, removingsaid magnets and layers as a unit from said fixture, and casting saidunit in a rotor and finishing said latter layers in a true cylindricalsurface concentric with said rotor and disposing said surface at oneside of an air gap in said magneto.

4. A magneto structure comprising a rotor havin in combination, a, pairof circumferentially spaced magnets, a rotor of magnetic material inwhich said magnets are carried, said magnet having layers of sprayedhighly magnetic material on their inner and outer pole faces, the outerof said layers being in close en gagement with a magnetic portion ofsaid rotor whereby said rotor forms a magnetic path between said magnetsand the inner of said layers being finished in a true cylindricalsurface concentric with said rotor.

5. A magneto structure comprising a rotor having in combination, a pairof circumferentially spaced magnets, said magnets having layers ofhighly magnetic material sprayed onto the inner pole faces thereof andhaving a layer of highly magnetic material sprayed onto the outer polarfaces thereof and extending between said magnets and a rotor ofnon-magnetic material in which said magnets are cast whereby said outerlayer forms a magnetic path between said magnets.

6. A magneto structure comprising a rotor, having in combination, a twinmagnet having circumferentially spaced polar faces at its inner side,layers of highly magnetic material sprayed onto said inner face andforming an integral part of said faces and a rotor of magnetic materialin which said magnet is cast, said layers of highly magnetic materialbeing finished in a true cylindrical surface concentric with said rotorand being located at one side of the air gap in said magneto.

DANIEL A. ARMSTRONG. WALTER J. RALEIGH. JOHN C. BANDLI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 578,280 Turner 'Mar. 2, 18971,100,602 Morf June 16, 1914 1,792,530 Coughlin Feb. 17, 1931 1,947,493Rose Feb. 20, 1934 1,986,856 Ringel Jan. 8, 1935 2,048,222 Rehmann July21, 1936 2,060,260 Spengler Nov. 10, 1936 2,164,737 Ford July 4, 19392,300,400 Axline Nov. 3, 1942 2,442,638 Cioffi June 1, 1948 2,469,196Goldberg May 3, 1949 FCREIGN PATENTS Number Country Date 150,273 GreatBritain June 30, 1921

